Tap A takes 8 minutes to fill an empty fish tank of dimension 40 cm width by 120 cm length and unknown height with water to the brim.
Tap B takes 6 minutes to fill the same empty fish tank with water to the brim.
Tap C takes 4 minutes to drain all the water out from the full fish tank.
How long does it take for the water to overflow from the fish tank, given that the fish tank is half-filled and all 3 taps are turned on at the same time?